Your brain on saturated fat

Fatty foods make you lazy! In fact, a diet high in saturated fat is detrimental to the brain system that controls motivation—an effect that occurs well before any weight gain. According to Stéphanie Fulton, researcher at the CHUM Research Centre and professor in the Department of Nutrition at Université de Montréal, that is the very reason why people who consume a lot of fast food generally lack motivation to exercise.

The body constantly seeks more fat to feel equivalent satisfaction at each meal.

Fulton and her team reached the conclusion based on their studies of three groups of rats that were put on different diets: a low-fat diet, one high in monounsaturated fat (olive oil) and a third high in saturated fat (palm oil). After eight weeks, all of the rats had a comparable weight. But when behavioural and biochemical tests were carried out on the animals, the researchers noticed that the reward systems in the brains of the rats that had been fed a diet high in saturated fat were unbalanced. The reward system is a circuit of nerve fibres meant to provide the motivation required to carry out vital functions such as eating and drinking by triggering a sensation of wellbeing.

According to Stéphanie Fulton, the long-term consumption of bad fats—saturated, trans and hydrogenated—short-circuits the reward system. The body constantly seeks more fat to feel equivalent satisfaction at each meal and loses the drive to exercise. The researcher also believes that the fat causes an inflammation of the circuits that control mood, anxiety and despair that could lead to depression. A study to validate the hypothesis is currently underway.